Thumb knob attachment for mortise-type lock



April 1, 1969 J. muss 3,435,544

THUMB KNOB ATTACHMENT FUR HOR'IISE-TYPE LOCK Filed Oct. 27. 19s? "16.6 i. 32 INVENTOR.

A ril 1, 1969 J. HINES 3,435,644

THUMB KNOB ATTACHMENT FOR MORTISE-TYPE LOCK Filed Oct. 27, 1967 Sheet 2 of 2 J0 Inga. I I .Z w v 94 15 p jfig 7 -20 M ii' HM. i Hill 7.6

INVENTOR.

United States Patent U.S. Cl. 70-129 4 Claims ABSTRACT OF THE DISCLOSURE A thumb knob attachment sub-assembly, for a mortisetype lock, which comprises a pair of toggle arms, each pivoted at one end to a base member with their free ends urged toward one another by a coil spring interconnected between points intermediate the ends of the toggle arms respectively, to press on the outer surface of a cam carrying bushing, which extends through the base member and is wider in one cross section dimension than in another normal to it, and has relatively long fiat sides at its narrower dimension and shorter curved sides at its wider dimension. No part of the coil spring is subjected to severe strain and it has long life, functioning to hold the bushing so that the cam thereon will not move, with, or relative to, a supporting spindle, due to vibration or jarring, into a position where it will prevent the bolt of the mortise-type lock from being moved by other means, usually operated from outside a door, such as a cam attached to the inner end of the plug of a key operated cylinder lock.

This invention relates to improvements in the mortisetype lock subassembly known as the thumb knob attachment.

In locks of this kind a casing is inserted in a space within a door, opening from the front edge of the door, and in the casing a bolt is provided for reciprocation between locked and unlocked positions. Latch means coacting with a lug in the casing normally holds the bolt in fully locked or fully unlocked position. The latch can be released by either of two cam members, one of which is a part of the thumb knob attachment subassembly and is operated from inside a door by a thumb knob, and the other of which is attached to the plug of a cylindertype lock and is operated from outside a door by rotating the plug with the proper key. When either the cam means operated from the outside of the door, or the cam means operated from inside the door, is turned to lock or unlock the door, it first swings into a position between two contact shoulders on the bolt and contacts the latch and moves it to inoperative position, and it then contacts one of said shoulders, depending on whether the door is being locked or unlocked, and moves the bolt until the bolt is fully home, in locked or unlocked position, and then clears the shoulder and continues its swinging movement to its at rest position, which, in the case of the cam operated by the thumb knob inside the door is a horizontal position parallel to the bolt, and in the case of the cam operated with the plug of the cylinder lock, from outside the door, is a vertical position extending away from the bolt.

Difiiculty has been encountered in the past with locks of this kind because the means employed to hold the thumb knob operated cam out of contact with the shoulders of the bolt, so that the key controlled cam can operate, has been very unsatisfactory since it has a very short life and breaks after very limited use, after which there is nothing to prevent jars and vibration to which the door is subject from turning the thumb knob attachment cam to a position where it is opposed to one of the shoulders of the bolt, making it impossible to actuate the other cam and move the bolt in the direction opposed by the thumb knob attachment cam. Thus even a person equipped with the correct key may be locked out.

Heretofore it has been attempted to return the thumb knob controlled cam to rest position, clear of the shoulders on the bolt, by providing two spaced, straight, parallel contact members disposed on either side of a bushing which, when rotated, pushes outwardly against the members and bends them at their fulcrum points. This means, illustrated in FIGS. 10 and 11, has proven unsatisfactory. The repeated bending of the contact members weakens them and they break, usually at, or adjacent to, the fulcrum points, and unless and until replaced there is the risk and the likelihood of the thumb knob attachment cam member being turned, by vibration or inadvertantly in any way, to a position in which it opposes a shoulder of the bolt thus prohibiting movement of the bolt by the key actuated cam.

Accordingly it is an object of this invention to provide an improved means for causing the cam of a thumb knob attachment to assume and maintain a position out of contact with the dead bolt, and which will be subject to much less stress and will have much longer life than the means used in the prior art and will therefore contribute toward a more dependable lock, and greatly reduce the chance of a person being inadvertently locked out.

An object of the invention is to provide, for mortisetype locks of the kind described, an improved thumb knob attachment subassembly capable of long wear and therefore not requiring the frequent replacement which is characteristic of the prior art devices and those which have been commercially available prior to this invention.

The invention will be best understood by reading the following description in connection with the drawings in which:

FIG. 1 is an isometric view showing a portion of a door with a mortise-type lock of the kind described positioned therein,

FIG. 2 is a side elevational view of a vertical section through the door and casing, one side wall of the casing being removed, showing the bolt latched in fully unlocked position with the thumb knob controlled cam member 'in its at rest position,

FIG. 3 is a horizontal sectional view taken on the lines 33 of FIG. 2,

FIG. 4 is a vertical sectional view taken on the lines 4-4 of FIG. 2,

FIG. 5 is a view similar to FIG. 2 but showing the bolt being unlatched by the thumb knob controlled cam, and unlatched by the thumb knob controlled cam, and moved from unlocked to locked position,

FIG. 6 is a view similar to FIG. 5 but showing the bolt after it has been moved to fully locked position and with the bolt latch, and the two cam members in their respective at rest positions.

FIG. 7 is a front view of a thumb knob attachment subassembly embodying the invention,

FIG. 8 is a vertical cross section taken on the lines 8-8 of FIG. 7,

FIG. 9 is a horizontal section taken on the lines 9-9 of FIG. 7,

FIG. 10 illustrates one prior art form of a thumb knob attachment assembly, and

FIG. 11 illustrates another such prior art assembly.

The subassembly embodying my invention, as shown in FIGS. 7-9, comprises the back plate or base 10 which is formed with a horizotnal slot 12, to receive a coil spring 26, and an aperture 13 to receive a bushing 14 which is rotatable in the base and has a portion extending beyond the inner surface of the base as a tubular projection 16, which is longer in one plane than in a second plane normal to the first plane, and has the relatively long, flat, parallel sides 16a and 16b, and the shorter, curved sides 17a and 17b.

On the rear face of base the toggle arms 18 and 20 are pivotally mounted adjacent their upper ends by the pivots 22 and 24 respectively. The lower ends of the toggle arms are disposed on either side of the bushing tubular extension 16, and normally are held in abutting relation to the flat sides 16a and 16b of projection 16 by the action of the coil spring 26 which is disposed within the slot 12, its opposite ends being connected to the pins 28 and 30 which are mounted on the toggle arms respectively intermediate their ends.

Mounted on the bushing extension 16 is a cam 32 which comprises, a hub portion 32a apertured to receive the bushing extension 16 of bushing 14 which may be peened over to provide positive engagement of the bushing extension 16 with the hub portion 32a of the cam. Projecting in opposite directions from the hub portion 32a are the two cam arms 32b and 320. The bushing 14 and its extension 16 define an axial passage 33 which is square in cross section and adapted to receive the knob spindle 34 which is also square in cross section, and which extends through a wall of the casing 36 of a mortise-type lock assembly to the inside of the door, the thumb knob 38 being secured on the spindle 34 on the inside of the door. When the thumb knob 38 is turned the engagement of the spindle 34 within the bushing 14 causes the bushing and cam 32 thereon to be rotated, and as the longer diameter of the extension portion 16 of the bushing becomes progressively interposed between the lower free ends of toggle arms 18 and 20 they are moved apart against the force of coil spring 26, and they are moved back by the action of coil spring 26 as the shorter diameter of the extension portion of the bushing is again presented between the toggle arms, thus returning the cam 32 to its at rest position.

Because the pins 28 and on the toggle arms respectively, to which the ends of the coil spring are attached, are disposed intermediate the ends of the toggle arms, the pins 28 and 30 will not be moved apart as much as the lower free ends of the toggle arms and us the movements of the coil springs in a longitudinal plane in expanding and contracting are relatively small subjecting the spring to relatively small tension.

It will also be noted that because a coil spring is employed apart of the tension is absorbed by each turn of the spring and there is no bending of a contact member around a fulcrum point such as occurs when the straight arms 40, 42 and 44, 46 of the prior art devices shown in FIGS. 10 and 11 respectively are bent outwardly as the extension of the bushing employed therein, which is similar to the extension 16 shown in FIGS. 7-9, is rotated from a position in which its narrower diameter is opposed to the arms to a position in which the wider diameter of said extension is opposed to the arms. The repeated bending to which the straight arms of the prior art devices shown in FIGS. 10 and 11 are subjected causes the arms to fail, usually breaking at the points around which the arms pivot, which in FIG. 10 is at the mounting pin 48, and in FIG. 11 is at the points -50 and 52 where the arms pass through apertures in the base.

It has been found that mortise-type locks equipped with thumb knob attachment subassemblies as shown in FIGURES 10 and 11 are frequently and repeatedly returned to the manufacturer for repair by substitution of a new thumb knob attachment subassembly. In use thumb knob subassemblies of the kind shown in FIGURES 7-9, and claimed herein, have much longer life than the prior art devices thus substantially freeing the mortise-type lock user from the difficulties, embarrassment and expense which is occasioned when a person equipped with a correct key finds himself nevertheless locked out by the blocking action of the cam comprising part of the thumb knob attachment subassembly due to failure of the means by which the said cam member is normally held in an at rest position, clear of the shoulders of the bolt referred to above.

A mortise-type lock in which thumb knob attachment subassemblies are employed, is shown in FIGURES 1-6. A mortise-type lock assembly 60 is inserted from the front edge of a door 62. Extending through one wall of the assembly casing 36 to the outside of the door is a cylinder type, tumbler lock 64, of known construction, comprising the cylinder 66 through which extends a cylindrical passage in which a plug 68 is rotatably mounted, the plug being provided with a key slot 69, the insertion of a correct key 70 in the key slot 69 serving to raise tumblers, not shown, Within opposed bores, not shown, in the cylinder and in the plug, to the line of parting between the cylinder and the plug, so that the plug can be rotated by the correct key, as will be understood by those skilled in the art. At the inner end of the plug 68 a cam 72 is provided and, although it is not in any way connected with the cam 32 comprising part of the thumb knob attachment subassembly indicated generally in FIGURES 3-7 by the numeral 74, it is disposed in a plane adjacent to, and parallel with, the plane of cam 32, and both of said cams 32 and 72 are positioned so that as they are rotated, by the thumb knob 38 or by correct key 70 respectively, they will move into the space between two shoulders 76 and 78 projecting upwardly in spaced relation from adjacent the inner end of the bolt 80, and will move into contact with one end 82 of the latch member 84 which is pivotally mounted to the bolt at 86 and is urged by the spring 88 to rotate in a counter clockwise direction so that the head portion 90 of the latch will be interposed in front of the lug 92 within the casing, when the bolt is in fully locked position, and will be disposed behind the lug 92 when the bolt is in fully unlocked position.

One side wall of the casing 36 is removable, a screw hole being provided in the side wall for a screw which engages in an internally threaded boss 93 projecting from the inside of the other side wall of the casing. The boss 93 is positioned to coact with the lug 92 in providing a slideway for the dead bolt 80.

After whichever cam is moved into contact with the end 82 of the latch 84, and has rotated it against the force of spring 88, thus conditioning the bolt for movement, along the slideway between lug 92 and boss 93 and has moved the bolt either into fully locked position or fully unlocked position, the cam is then able to clear the shoulder 76, or shoulder 78, as the case may be, the shoulders adjacent their upper ends having the beveled faces 77 and 79 respectively to provide clearance for the moving cam.

It will be understood that since a key cannot be withdrawn from key slot 69 of the plug 68 of a cylinder lock except when the plug is in fully locked or fully unlocked position the movement of a single arm cam 72 carried by the plug, is through 360 from an initial position extending vertically upward, and it is moved through the 360 due to the fact that the person with a key must turn the plug through 360 in order to either lock or unlock the cylinder lock and free the key.

The cam member 32, comprising part of the thumb knob attachment subassembly, has the two arms 32a and 320 spaced apart by 180, and movable through 180 from an at rest position parallel to the bolt, the position of arms 32b and 32c being interchanged each time the thumb knob 38 attachment assembly is rotated through 180.

The thumb knob attachment subassembly may be secured within the casing in any desirable way. As shown herein notches n are provided on opposite sides of the base and screws 94, with tapered ends to engage in the notches n, may be inserted into the casing, as, for example, through the face plate 96 of the casing.

There has thus been provided a thumb knob attachment assembly in which the objects stated above are accomplished in a simple and practical way.

What I claim is:

1. A thumb knob attachment subassembly for mortisetype locks comprising a base, a pair of toggle arms, and means for pivotally mounting each of them at one end to the base, a member mounted for rotation in the base between the free lower ends of said toggle arms, said member having a lesser CI'OSs sectional dimension normally opposed to said arms and a greater cross sectional dimension which is progressively interposed between said arms as the member is rotated through 90, a cam mounted on said member and comprising arms normally disposed at right angles to the greater cross sectional dimension of said member, and a coil spring interconnected between said toggle arms intermediate their ends.

2. The thu-mb knob attachment subassembly claimed in claim 1 in which the base member is apertured to receive a rotatable bushing extended beyond the inner face of the base member as a tubular member having a cross section longer in a first plane than in a second plane which is normal to the first plane, the cam member being mounted on the bushing extension for rotation with the bushing and bushing extension and comprising a hub portion and two arms extending radially from the hub portion in opposite directions, the bushing defining a noncircular sleeve to receive a spindle which is noncircular in cross section, and a thumb knob for mounting on one end of said spindle and adapted when turned to rotate the spindle and the bushing and the cam thereon through 180.

3. The subassembly claimed in claim 1 in combination with, a casing for a mortise-type lock assembly having therein, a bolt movable between locked and unlocked positions, a latch yieldingly holding the bolt in fully locked or fully unlocked positions, the bolt comprising two shoulders'spaced apart, and the latch having an end portion disposed between said shoulders, means for fixing the base of the thumb knob attachment within said casing with the cam which comprises part of said subassembly normally disposed in an at rest position substantially parallel to the bolt, and related to the bolt so that when it is rotated through 180 one of the arms of said cam will swing into the space between said shoulders and contact the end portion of the latch and move the latch to condition the bolt for movement, and thereafter contact one of said shoulders and move the bolt to fully locked or fully unlocked position, after which said coil spring means acting through said toggle arms will urge the said member and cam to return to at rest position and hold the cam out of the path of said shoulders, thereby permitting the latch to be released and the bolt to be moved by other means such as cam means which is actuated by turning a cylinder lock plug with a key.

4. The subassembly claimed in claim 1 including in combination, a mortise-type lock casing, a bolt mounted for reciprocation within the casing, a latch for holding the bolt in locked and unlocked positions, and a plurality of separately operable cams, including as one of the cams the one comprised in said subassembly, each positioned so that when operated it will release said latch and move the bolt between locked and unlocked positions.

References Cited UNITED STATES PATENTS 967,111 8/1910 Dawes 194-85 2,042,021 5/1936 Schlage -129 X 2,178,666 11/1939 Larson 292 2,616,738 11/1952 Jewett 292-140 2,697,419 12/1954 Krohm 74107 X 3,027,183 3/ 1962 Schlage 292140 RICHARD E. MOORE, Primary Examiner. E. J. MCCARTHY, Assistant Examiner.

U.S. c1. X.R. 292-140 

